Electric motor.



No. 660,7l3. Patented Oct. 30, I900. T. S. WATSON. ELECTRIC noTon.

(Application filed Oct. 4, 1899.\

2 Sheets-Sheet I.

(No Model.)

N0. 660,7!3. Patented Oct. 30, I900.

T. S. WATSON.

ELECTRIC MOTOR.

(Application filed Oct. 4, 1599. (In Nodal.) 2 Shaeta-Sheot 2.

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UNITED STATES PATENT OFFICE.

THOMAS S. WATSON, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE BROWNING MANUFACTURING COMPANY, OF SAME PLACE.

ELECTRIC MOTOR.

SPECIFICATION forming part of Letters Patent No. 660,718, dated October 30, 1900.

Application filed October 4,1899. Serial No. 732,442- (No model.)

To ctZZ whom it may concern.-

Be it known that I, THOMAS S. WATSON, a citizen of the United States, and a resident of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Electric Motors; and I do hereby declare that the following is a full, clear, and exact description thereof.

.My invention has especial reference to that class of electric motors particularly design ed for the operation of rotary dental tools, although not necessarily restricted thereto; and it consists in certain peculiarities of construction and combination of parts, as will be fully set forth hereinafter and subsequently claimed.

In the drawings, Figure 1 is a front elevation of my motor arranged in a suitable standard in connection with a controlling device for operating a dental engine. Fig. 2 is an end view of said motor with its protectingshell removed, showing also part of the supporting-standard in section and drawn to an enlarged scale. Fig. 3 is a sectional view of said motor, taken on the line 3 3 of Fig. 4. Fig. 4 is another sectional view of said motor, taken on the line 4 4 of Fig. 3.

Referring by letter to the drawings, A represents the supporting-standard,consisting of a hollow shank terminating in a flat baseplate a, which rests upon the upper surface of an electric-motorcontrolling device or switch apparatus B, to which the said baseplate a is secured by screws, as shown, the controlling device B having suitable legs Z) b, which thus become the legs or supports of the motor-standard A. At its upper end the said standard A is expanded into a ring C, having a socket c at the top for the reception of an arm D, which in turn at its upper end is formed with a socket d to receive the lower end of the rod E, designed for the support of the usual flexible shaft (not shown) of a dental engine rotated by a belt (also not shown) from a pulley e on the hereinafter-described armature-shaft I.

Fitting within the standard-ring C is the annular frame F of my field-magnet, formed integrally with the shanks f f of the polepieces G G, the latter being made separate and independent from the pole-shanks, to which they are afterward secured by the screws g g, as hereinafter explained.

H H indicate the field-coils fitting around the pole-shanks ff, as shown. The opposed ends of the pole-pieces G G are secured together by the connecting-pieces h t, which are made, preferably, of brass or other non-magnetic rnaterialand formed with central hubs for the reception of the shaft I of the armature J and its commutator K. The connecting-piece t' has two metallic strips j j connected thereto, one on each side, but insulated therefrom, as shown.

L L indicate brushes for engagement with the commutator K, which brushes are pivotally attached one to each of the said stripsj, as shown best at min Fig. 2, and held against said commutator by springs 77,. The hubs of the connecting-pieces 7t 4 are provided with holes 0 0, whereby the shaft I is lubricated by means of oil-cups, (indicated by the dotted circles 19 p.)

In assembling my motor after the fieldcoils H H have been slipped to place upon the pole-shanksffthe armature J,commutator K, and shaft 1, with the pole-pieces G G, connecting-pieces h 1 and brushes L L, are slipped to place, with the screw-threaded bores in the said pole-pieces in line with the bores through the pole-shanks ff and ring C of the standard A, and then the screws 9 g are inserted and tightened. Next the semispherical shells M M are adjusted to place, inclosing the motor, as shown in Fig. 1, one of said shells having a central hole for the passage of the shaft I therethrough. The described ring C is undercut on its opposite edges for the reception of the adjacent edges of the said shells M M, which are then fastened securely by means of the screws (1 q, passing through said ring C and clamping the shells against the described annular frame F of the fieldmagnet. Then the pulley e is secured to the projecting end of the shaft- I.

As heretofore stated, the standard A is hollow, and the conducting-wires pass up through the same from the controlling device B and through openings in the ring C and annular frame F, all as shown best in Fig. 2, the wires 4 1' leading to the strips j j and the wires .9 s

to the field-coils II II and being properly connected, as shown, all of said conducting-wires being thus concealed and protected within the standard of the motor.

The electric-motor-oontrolling device or switch apparatus B may he of any suitable or preferred construction, with the usual ca ble leading from the source of electric supply and with conducting-wires leading up to the motor, as just explained; but by having the said conducting-wires all extending up within the hollow standard and by having the latter mounted upon the controlling device, as Shown in Fig. 1, a much neater and more compact and convenient device is produced than where the controller is located ata distance from the motor-support and connected thereto by exposed cables.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination with a suitable hollow standard expanded into a ring at its upper end, said ring being undercut on each inner edge, of an annular magnet-frame, comprising a continuous metal ring having opposed inner shanks integral therewith, fitted within the said standard -ring, field -coils on said shanks, separate curved pole-pieces secured to said shanks by screws passing therethrough and through both of said rings; connectingpieees uniting the opposed ends of said polepieces, a shaft journaled in said connectingpieces, an armature and commutator on said shaft, insulated metallic strips secured to one of said connecting-pieces, spring-controlled commutatonbrushes hinged to said strips, series of conducting-wires leading up through said hollow standard, and connected, respectively, to said strips, and to said fieldcoils, and semispherical shells clamped between the annular magnet-frame and the standard-rin g, one of said shells having a central aperture for the passage of the armatuire-shaft therethrough.

2. In an electric motor for rotary dental tools and the like, the combination with a hollow standard expanded into a ring at its upper end, a motor having an annular magnetframe fitting within the ring of the standard, conducting-wires leading up through said hollow standard and connected to said motor, and semispherical shells fastened to said standard-ring and inclosing said motor, one of said shells having a central aperture for the passage of the shaft of the motor therethrough.

3. In an electric motor for rotary dental tools and the like, the combination with a motor-controlling device, of a hollow standard secured to and rising from said controlling device and expanded into a ring at its upper end, a motor having an annular magnet-frame fitting within the ring of the standard, conducting-wires leading up from said controlling device through the hollow standard and connected to said motor, and semispherical shells fastened to said standard-ring and inclosing said Inotor, one of said shells having a central aperture for the passage there through of the motorshaft.

In testimony that I claim the foregoing I have hereunto set my hand, at Milwaukee, in the county of Milwaukee and State of /Viscousin, in the presence of two witnesses.

THOMAS S. WATSON.

Witnesses:

H. G. UNDERWOOD, B. 0. 110mm. 

